A slight nit-pick, though I was going to say the exact same thing - `|| 0`. If you do `|| 1` the compiler's going to optimize the entire 'or' expression out ;)
I was thinking that using `0` would cause a problem when you select none of those compilation options, but then I realize the code won't even compile if you don't select at-least one (You get empty parenthesis fallowing the '&&' in the 'if' statement), so it doesn't seem like a big deal.
It's been a long time since I've done bare C, but are there now IDEs/editors that let you toggle the define statements you want to activate which then format the code without the ifdef/endif cruft to let you better conceptualize the actual source?
(edited to hide my shame)